1. Field of the Invention
The present invention relates to a cryopump system and a method of operating the same, and a compressor unit suitable for use in the cryopump system.
2. Description of the Related Art
Refrigerating systems including a cryogenic refrigerator and a compressor for supplying compressed gases to the refrigerator are known. When a reduction in a refrigerating performance is tolerated, the gas is allowed to flow into a buffer volume to reduce a static charge pressure of a gas circuit of the compressor. When a high refrigerating power is demanded again, the gas is discharged from the buffer volume to restore the static charge pressure. This allows the static charge pressure to be changed, while keeping the compressor operating at a constant speed. Electric power consumption is thus reduced when a reduction in the refrigerating performance is tolerated.